Variable-counterweighted door.



' A. T. PRESCOTT. VARIABLE coumerawamu'nzo noon.

APPLICATION FILED DEC. I5fli9l5- l lt w a Patented May 16; 191%.

3 SHEETS-SHEET I.

v A. T. PRESCOTT. VARI ABLE COUNTERWEIGHTED DOOR.

APPLICATION FILED DEC.15|1915.

Patented May 16, 1916.

3 SHEETS-SHEET 2.

A. T. PRESCOTT. VARIABLE (IQUNTERWEIGHTED DOOR.

APPLICATION HLED DEC-15. \915.

Patented May16,1916..

g fz/ A ATTOH/IEV ARTHUR. T. PRESCOTT, OF EAs'r ORANGE, NEW JERSEY, AssIGrToE To GEORGE H. E oTHINeHAM oOMPAEY, OF NEW YORK, N. Y., A CORPORATION or NEW YORK.

VARIABLE-CO'UNTERWEIGHTED DOOR.

Specification of Letters Patent.

. Patented May 113, 1916.

To all whom it may concern Be it known that I, ARTHUR T. PREsooTT,

a citizen of the United States of America,

and a resident of East Orange, Essex county, and State of New Jersey, have invented certain new and useful Improvements in Variable-Counterweighted Doors, of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof.

My invention relates to improvements in doors of the type which are used to close large openings such as are on pier sheds, warehouses, and the like, and its objectis to provide a simple, reliable and inexpensive means for effectively counterbalancing such doors and thus making them more easily operated and safer in use. This has always been a serious problem with doors of certain otherwise desirable types, because of the fact that the load to'be counterbalanced varies materially and irregularly during their operation, and the fact that these doors are often massive has aggravated the difliculties to be overcome.

To overcome these difiiculties especially as found in multiple section doors, is another purpose of this invention.

These and other objects of the invention willappear in the following specification,

in which I will describe the invention, the

novel" features of which will be set forth in appended claims.

Referring to the drawings: Figure 1 is an elevation of a .door of one of the types to which this invention is applicable, together with my novel counterweighting arrangement embodied therewith. Fig. 2 is a sectional side elevation of. the door shown in Fig. 1, showing the door in its closed position, and Fig.3 is a similar view of the same parts with the door open. Fig. 4 is an end elevation showing diagrammatically another of the many types of doors to which this invention may be applied. Fig. 5 is an elevation which diagrammatically shows such a door as isillustrated in the preceding figures, together with a counterweighting arrangement which embodies my inven-" tion. Fig. 6 is a sectional end elevation of 'a part of the mechanism shown in Fig. 5,

the section being taken on the line 66 of the latter figure.

Fig. 7 is a view similar to Fig. 5 and illustrates a modified construetion which 'also embodies my invention. Fig. 8 is a similar View illustrating a still further modification of'the invention. Figs. 9 and 10 are respectively an elevation and a sectlonal end view of a counterweight drum whlch is a detail of a constructionused in the mechanism which is illustrated diagrammatically in Fig. 5. 1

Like characters of reference are designated by the same reference. numerals in each of the figures.

10 designates the lower section of a door, the lower corners of which are guided to have a vertical movement equal to the helght of the door opening. This may be accomplished by providing rollers 11 at the lower corners of this door section and vertical tracks 12 for the rollers to run in. ThlS lower section is arranged to be moved up in guides 13 on ,the edges of an upper door section 14: on the edges of which are pivoted rollers 15 which are guided to run 1n a curved track such as 16 in Figs. 2 and 3, or in a track such as 16A in Fig. 4:, with two connected straight portions one of which is inclined in relation to the other. Such doors are lifted by means of chains 20 attached to the lower corners of the lower door section at 21, which chains run over pocket sheaves 22 affixed to a shaft 23 which is arranged to be rotated by a hand chain 24 through suitable gearing 25. The chain 20 may be an endless chain running under a pulley 26 on a fixed pivot, and may carry a counterweightQ'Z. It is obvious that the combined weights of the two counterweights 27 cannot be greater than the weightof the lower door'section 10 or the latter will not remam closed.

I prefer to provide another counterweight 3O suspended from a chain 31 which is wound upon a drum 32 aflixed to shaft 23.

:A portion 33 of this drum is cylindrical and the amount of chain 31 which is wound upon thls portion corresponds in length with the length of the first movement ofthe lower door section 10in opening the door. This first movement of the lower door section is that which occurs in moving it .up back of door section 14 in guides 13. When the llmit of this first movement has been reached, a shoulder 17 projecting from the lower edge of the lower door section 10 will engage the lower edge Of the upper door together, the chain 31 will reach apart 34 of the drum of greater diameter. This will increase, the radius of leverage of the counter-" weight 30 on shaft 23 and effectively coun terbalance the combined weights of. the two' door sections. 1 From then on the li'ft of the door sections, will cause the.rollers to run out on tracks 16 and to swing the door sec- '.tions back until they gradually assume a horizontal position, as shown in Fig. 3. It is to be. noted that-more and more of the weight of the door becomes sustained. by the tracks 16 during this part of the operation,

so that there is a gradually decreasing H amount of this weight that needs to be counterweighted. Consequently the diam-- lighter one.

eter of the drum is gradually reduced as the is wound a'chain from the free end of' which is suspended a counterweight 48. The parts 43 and 47' are not neoessarily'true cones but are preferably so proportioned as to make the efiect of the counterweights properly proportioned to the'variable weights of the doors which they are designedto support.

In the embodiment of the invention which is shown in Fig. 8, the. hoisting chains 20 run over pocket sheaves 22 on sha-ft 23 to counterwelghts 27 as before, but the'upper door section is counterbalanced by means of chainssuch as 5.0 affixed to their lower corners asat 51 running up over sheaves such as 52 and down to a series of L-shaped Weights 53 which are pivoted together as at 54, the lower one of which is pivoted to a bracket 55 which is fastened to the floor 56. When this. door is opened the counterweights 27 have a uniform elfectlthroughout the whole movement of the door. When the door section 14 is picked up the weights 53 which counterbalance it are lowered and one by one become supported by the floor. In

chain is unwound' from it spirally, to .de-

crease gradually the counterweighting effect.

In closing the door the operation is' reversed and so is the cycle" of the counterweighting effect. I y r In connection with Figs. 5 and 6, attention may be called tothe fact that if the hoisting chains 20 are made endless and fun under pulleys 26, they need carry no counterweights 27 but that if counterweights 27',

are used the counterweight 30 may be a It may also be noted that if thetcounterweights 27 are sufliciently heavy to'holdthe chains 20 in engagement with the pocket sheaves 22, they need not be endless but may terminate at the points 21 and at the top of the counterweights 27. Such an" arrangement is shown in Fig. 8.

In Fig. 7 the hoisting chains 20 are each arranged to be wound up on a portion 40 of a drum on shaft 23, and eachof the chains from counterweights 4:1 is simultaneously unwound from another part 42 of the same drum. If the'part 40 is cylindrical, the part 42 upon which the first part of the chain is wound'is also cylindrical, this part of the chain being the partwhich is un-' wound 'while the lower doorlsection 10 is moved up on to the upper door section.

The part.43 of the drum from which the" chain 41 is .unwound is in the form ofa decreasing cone which decreases the efi'ecteof the-counterweight on the door as a part of its-weight becomes supported by track 16.

' Other chains such as 44 are connected to.

the lower corners of the upper door section and each of these is arranged to be wound -counterweight suspended from the free end Y up on a drum 46 rotatably supported near the top of the door opening. Apart'47 of this drum is conical andon this conical part other Words they have a decreasing effect upon the door sections as the latter are moved from their.vertical to their 'horizonlift door adapted during a part of its movement to be swung. out of 'a' vertical plane and having means for sustaining a part of the weight of the door when it is out-of its verticalposition, hoisting means for said door, variable counterweighting means for the door, and mechanism connecting said counterweighting means with the door, said mechanism comprising means actuated by the movement of the door for increasing the effect of said counterweighting means upon the door as the number of its sections moved is increased and for decreasing the effect of said counterweighting means upon the door as a part of the weight thereof is taken up by said sustaining means.

2. In combination with a multiple section lift door adaptedrduring a part of its opening movement to be swung out of a vertical plane and. having means for sustaining a part of the weight of the door when 1t is out of its vertical position, hoistlng means for said'door comprising a rotary shaft, adrum I on said shaft of varying diameters, a fiexi-,

ble element wound around saiddrum, and a of said flexible element, the-diameters of said drum varying in relatlon 'to the dlf- "ferent parts of the movement of the door to [vary the effect of the counterweight on the 3 door to have itsmaximum effect during an intermediate part of the movement of the door and a gradually'decreasing effect during the remainder of the movement of the 3. In combination with a multiple section lift door adapted during a part of its opening movement to be swung out of a vertical plane and having means for sustaining a part of the weight of the door when it is out of its vertical position, hoisting means for said door comprising a rotary shaft, a 'drum on said shaft, a flexible element wound around said .drum', and a counterweight suspended from the free end of said flexible element, a portion 'of said drum being cylindrical, an-adjacentportion thereof having a larger diameter than that of the cylindrical portion and the remainder of said '20 drum bein .of cone-like form.

4. In combination with}. lift door H to be swung out of a/vertical plane and havmg weight of the door when it is out of its means for sustaining a part of the ma ame adapted during a part of its opening movement tical position, and hoisting means for said door; of counte'rweighting means for the door, and a mechanism connecting said counterweighting means with the door, said mechanism comprising means actuated by the movement of the door for irregularly varying the effect of said-.coun terweighting means upon the doorduring difl'erent parts of the. movement of the door to have its -maximum effect during an intermediate in, a chainwound around said drum when vertical position, and heisting' means for said door; of counterweighting means for the door, and'a mechanism connecting said counterweighting means with the door, said -mechanism'comprising means actuated by the movement of the door for irregularly varying the efi'ectof said counterweighting means upon the door during different parts ofthe movement of the door.

ed :during a part of its opening movement to bs swung out pf a vertical plane and havingi-"means for. sustaining a, part of the weightof the; door when it is out of its .ver-

the dooris closed, and a counterweight suspended from the free end of said chain, the portion of said drum from which the counterweight chain is unwound during the independent movement of the lower door section being cylindrical, an adjacent portion of larger diameter corresponding to the part of'the' door movement during which the upper-door section begins to move, and a 5. In combination with a lift door ada t- I cone-shaped" portion decreasing to a diame ter less than that of;the cylindrical portion.

In witness whereof, I have hereunto set.

myhand this 14th day of December,- 1915.

AR HUR r rREsco'rT. 

